Many container lid locking mechanisms have been proposed. An example of a container lid locking system is disclosed in U.S. Pat. No. 4,534,488. While the many container lid locking mechanisms have their uses, several shortcomings have become evident with respect to efficiently and effectively locking lids on large containers. Specifically, in the field of locking container lids for trash receptacles, there are few simple locking mechanisms, and even fewer retrofit automatic mechanisms which can be applied to a broad variety of types and sizes of containers.
With the advent of mechanized trash removal, there have been created a number of large sized trash bins. These bins usually comprise a block shaped container with a hinged lid attached to one side thereof. The container further includes attachments for accommodating various forked lifting mechanisms of the trash removal vehicle. The containers are lifted by the lifting mechanism of the trash removal vehicle and pivoted in some fashion so that the hinged top of the container opens and the trash contained therein is emptied into the vehicle. The container is then returned to a position on the ground, and the hinged lid closes on top of the container.
Many of these large trash receptacles are rented from a trash removal service. These receptacles are not provided free of charge, and consequently their frequent emptying and service can become a considerable expense. This expense is increased when unauthorized users of the receptacle freely deposit trash therein. This unauthorized use necessitates a more frequent emptying of the container, and of course the unauthorized user does not contribute to the increased expense.
For the foregoing reasons, there has existed a need to create a locking mechanism for these containers which is simple and reliable, and which can be originally and retrofitted to a broad variety of containers. While many of these containers are of all metal construction, and at that very fairly heavy gauge metal, many of the newer containers are of partial plastic construction or are of all plastic construction. Hence, the ability for a user or provider of the receptacle to attach a simple welded locking structure is limited owing to the fact that not all of the parts of the container can accommodate a weld.
A device has been proposed in U.S. applications Ser. Nos. 07/465,328, now U.S. Pat. No. 5,029,724 and 07/515,515, now U.S. Pat. No. 5,042,856 which solve many of the shortcomings of the prior art. However, the locking device proposed in the first referenced U.S. application cannot be automatically operated by the mere use of a trash removal vehicle to empty the container. Instead, the vehicle operator must leave the vehicle and unlock a securing chain so as to enable emptying of the container. After the dumping operation is complete, the operator must resecure the locking mechanism in the locked position. While the previously proposed device has advantages with respect to cost efficiency, the lack of automation may be considered a drawback in certain applications of the locking mechanism.
The locking mechanism proposed in the second listed application includes automatic counterweighted operation of a dumpster locking mechanism. As an improvement in the field of automatic locking mechanisms, the present invention proposes to take advantage of the weight of the container and the well established emptying cycle. The weight of the container secures the lock in place, and upon lifting of the container, a spring and/or gravity operated foot unlocks the device and maintains the device in an unlocked configuration during the dumping cycle.